The invention relates to a slewing device for screw closures, in particular, from plastic materials, for containers and comprising a drive and a torque limiter for controlling power supply to the drive and including a torque sensor and an angle of rotation sensor, and a method of placing screw closures on containers using the slewing device according to the invention.
A slewing device for screw caps or screw closures as well as a method for putting such closures or caps on containers are known (DE-OS 37 15 935). The known slewing mechanism serves for screwing screw caps onto receptacles and observe herein a preset closing moment. A torque limiter prevents exceeding the desired moment. For this purpose a control circuit measures the drive current absorbed by the drive motor of the rotational device and triggers control signals if the current rises to a specific value corresponding to a specific torque of the threaded-on cap or closure, by means of which the drive current of the drive motor is interrupted. Thus one directly affects the energy supply of the drive.
However it was seen that in some cases especially when using solid plastic closures, a secure sealing of the container is not achievable also when presetting a specific closure moment. This applies especially when containers or bottles subjected to an overpressure are to be closed. By presetting a specific closure moment it is in addition possible to damage the mouth region of the container to be closed, especially with glass bottles, which leads to danger for the consumer. Finally it is seen, that the opening moment, meaning torque required for initial opening of the container, is often considerably higher than desired.
It is therefore the task of the invention to create a slewing mechanism as well as a method, by means of which containers with screw closures, especially also those made of plastics material, can be closed, wherein containers subjected to overpressure are closed in a pressure-tight manner however without being damaged in the mouth region and where a specific opening moment is set up.